Weber let off problem

[bhendrik@flash.net]

Two weeks ago I came across the following  problem.  On a routine 
tuning service call on a Weber grand, I noticed severe blocking of 
hammers due to inadequate let off.  Looking  back on my service 
record I had noted making let off adjustment two years previous. I 
contacted the Weber service represenative and he said to problem was 
due to "spreading action brackets".  It seems as though this is a 
problem that has cropped up on some Weber, Young-Chang, and 
Chickering grands  manufactured between 1989 and 1991.  He explained 
as best he could how to replace the action brackets.  I recieved 
yesterday the replacement brackets from the Weber company.  Since I 
have never come across this problem before, nor seen any write up on 
it in the PTG journal,  or have heard any mention from fellow piano 
technicians on this problem, I was hoping some of you who may have 
encountered this problem and replaced these brackets, could give me 
some pointers.  Bill Marciano did mention to replace the end brackets 
first.  He also mentioned "maintaining a .112mm spread."  I am still 
a little unclear as to what exactly this term "spread"  means.  Any  
suggestions would be appreciated.  
                           Bill HendricksonRPT